Ectopic macrochaetae form on the scutellum in 55.2% of cases when NcC318G.Scer\UAS is expressed under the control of Scer\GAL4sca-P309. In contrast, the ectopic expression of NcC318G.Scer\UAS in SOP cells, driven by Scer\GAL4neur-GAL4-A101, does not result in extra macrochaetae. Larvae expressing NcC318G.Scer\UAS under the control of Scer\GAL4sca-P309 have one extra SOP cell in the scutellum region of the third instar wing disc. Analysis of the scutellum region of the pupal notum (24---30 h after pupal formation (APF)) shows that there is an extra neuron and thecogen present, which are derived from the extra SOP cell. No significant increase in macrochaetae number is seen when NcC318G.Scer\UAS is expressed under the control of Scer\GAL4hs.PB following a heat shock at late third-instar (6-12 h APF), which is during SOP cell formation, or after it (24-30 h APF). At the stage prior to the appearance SOP cells, however, NcC318G.Scer\UAS expression leads to extra macrochaetae formation.